Nigella Plants - Traditional Uses, Bioactive Phytoconstituents, Preclinical and Clinical Studies.

Bahare Salehi,Krishnendu Acharya,Hamed Azadi,Ahmad Faizal Abdull Razis,Hafiz Ansar Rasul Suleria,Yasaman Taheri,Muhammad Imran,Dima Mnayer,Usman Sunusi,Gautam Sethi,Miquel Martorell,Cristina Quispe,María Del Mar Contreras,Ramla Muhammad Kamal,Surjit Sen,Jelena Živković,Iahtisham Ul-Haq,Ibrahim M Abu‐Reidah ,Antonio Segura‐Carretero ,Javad Sharifi‐Rad

doi:10.3389/fphar.2021.625386

Abstract

Nigella is a small genus of the family Ranunculaceae, which includes some popular species due to their culinary and medicinal properties, especially in Eastern Europe, Middle East, Western, and Central Asia. Therefore, this review covers the traditional uses and phytochemical composition of Nigella and, in particular, Nigella sativa. The pharmacological studies reported in vitro, in vivo, and in humans have also been reviewed. One of the main strength of the use of Nigella is that the seeds are rich in the omega-6 fatty acid linoleic acid and provide an extra-source of dietary phytochemicals, including the bioactive thymoquinone, and characteristics saponins, alkaloids, and flavonoids. Among Nigella species, N. sativa L. is the most studied plant from the genus. Due to the phytochemical composition and pharmacological properties, the seed and seed oil from this plant can be considered as good candidates to formulate functional ingredients on the basis of folklore and scientific knowledge. Nonetheless, the main limations are that more studies, especially, clinical trials are required to standardize the results, e.g. to establish active molecules, dosage, chemical profile, long-term effects and impact of cooking/incorporation into foods.

Highlights

Nigella, known as fennel flower, is a small genus belonging to the family Ranunculaceae and includes around 20 species (Zohary, 1983; The plant list, 2020)
This was related with a decrease of the antioxidant activity (Bourgou et al, 2010a). This is essential information since water scarcity and salinization of arable lands may occur in a future scenario exposed to drastic changes caused by climate (Selim et al, 2019), affecting crop growth and its phytochemical content and antioxidant properties. This means that a high variability in the content of phytochemicals can be found in Nigella plant parts, and in particular in N. sativa seeds, and from a functional point of view each essential oil/extract should be further characterized in order to elucidate the real active molecules inside for further standardization and quality control
Nigella sativa fruit and seed extracts and oil (33% thymoquinone) have shown antiobesity potential using in vitro and in vivo studies, and the mechanisms include the inhibition of pancreatic lipase and α-amylase (15–100%, depending on the extract and enzyme), proinflammatory cytokine production in pre-adipocytes and weight loss, by positively affecting the uncoupling protein-1 (UCP-1), which the index protein of the brown adipose tissue used in the obesity studies (Buchholz and Melzig, 2016; Mahmoudi et al, 2018; Bordoni et al, 2019)

Summary

Introduction

Known as fennel flower, is a small genus belonging to the family Ranunculaceae and includes around 20 species (Zohary, 1983; The plant list, 2020). Salinity is another factor that greatly influenced the phenolic composition of Nigella seeds; e.g. generally the content of certain phenolic compounds decreased, including the major one vanillic acid (45), while the content of trans-cinnamic acid (53), FIGURE 4 | Example of chemical structures of phenolic compouds reported in N. glandulifera, N. sativa, N. damascena, and N. arvensis.

Results

Conclusion